Pneumatic sensors for the control of pneumatic cycles

ABSTRACT

Improvement in pneumatic sensors for the control of pneumatic cycles, in which a liquid jet vacuum pump is supplied at the input by a compressed air circuit and connected at the output to a nozzle of which the obturation provokes a rise in pressure in the vacuum pump used as signal for controlling a pneumatic component. The space 4 comprised between the jets 2, 3 of the vacuum pump is connected on the one hand to an output orifice 14 emitting the control signal and on the other hand to an airing valve 13b which, open during the ejection leakage, admits the atmospheric pressure in the space 4, the output 14 and the duct 15 preventing the creation of a depression and which is closed during obturation of the leakage. The invention is used for the control of pneumatic cycles.

The present invention relates to an improvement in pneumatic sensors forthe control of pneumatic cycles.

Pneumatic sensors, forming the subject matter in particular of BritishPat. No. 1 428 887, are known, in which a liquid jet vacuum pump isused, supplied at the input by a compressed air circuit and connected atthe output to a nozzle of which obturation provokes a rise in pressurein the vacuum pump which is transmitted to a pneumatic relay capable oftransmitting a pneumatic signal. However, the pneumatic relay is verycomplex and comprises an assembly of diaphragms and valves.

In order to overcome this drawback, a much simplified device giving verygood results is used according to the invention.

According to the invention, the space comprised between the jets of thevacuum pump is connected on the one hand to an output orifice emittingthe control signal and on the other hand to an airing valve which, openduring the ejection leakage, admits the atmospheric pressure in thespace, the output and the duct preventing the creation of a depressionand which is closed during obturation of the leakage, the supplypressure delivering and being established in the output, the duct thusforming the pneumatic pressure signal.

The device according to the invention therefore makes it possible toreplace a relay or a "yes" cell by a valve annulling the depression ofthe vacuum pump and thus allowing, in simple manner, the use of a vacuumpump for the emission of control signal of a pneumatic component.

The device presents considerable simplicity as it allows the use ofunions instead of complex apparatus with diaphragms, seats and multiplevalves.

The rise in pressure and the signal are obtained by the obturation ofthe leakage circuit which may be a simple orifice but also leakagecontactors of all types.

The leakage circuit may be integrated in the end-of-stroke switchapparatus employing signal but it may also be controlled electrically orpneumatically.

The signal emitted by the sensor may actuate by remote control allconventional distributor apparatus of all types.

The pneumatic signal emitted may be integrated in the apparatus and itmay be converted into an electrical signal.

Finally, the device allows a rapidity of decontrol by limitedaspiration.

Other characteristics and advantages of the invention will be morereadily understood on reading the following description of severalembodiments and with reference to the accompanying drawings, in which:

FIG. 1 is a view in section of a pneumatic sensor according to theinvention connected to a pneumatic circuit comprising a jack and itsdistributor and also another distributor.

FIG. 2 is a view in section of a variant embodiment of a pneumaticsensor according to the invention.

FIG. 3 is a view of a pneumatic circuit comprising a sensor in the formof a union.

FIG. 4 is a view in elevation of a sensor in the form of a banjo union.

FIGS. 5 and 6 are views of a pneumatic circuit provided with the sensorshown in FIG. 4.

FIG. 7 is a view in elevation of a sesnor in the form of a T-union.

FIG. 8 is a view of a pneumatic circuit provided with the sensor shownin FIG. 7.

FIG. 9 is a view in section of an embodiment of the leakage nozzle.

FIGS. 10 and 10a are views in section of a leakage nozzle comprising avalve and a ball control.

FIGS. 11 and 11a are views in section of a sensor comprising a means forobturating the leakage nozzle provided with a control roller.

FIGS. 12 and 12a are views in section of a sensor integrated in anapparatus with a leakage nozzle and an obturator.

FIG. 13 is a view in section of a distributor provided with integratedpneumatic sensors.

FIG. 14 is a view in section of a distributor comprising an integratedsensor controlling obturation of the leakage by an electrical means.

FIG. 15 is a view in section of a sensor in the form of a unioncontrolling obturation of the leakage by an electrical means.

FIG. 16 is a view in section of a sensor comprising an electrical outputsignal.

FIG. 1 shows an embodiment of a pneumatic sensor according to theinvention which comprises a body 1 presenting the form of a union andinternally comprising a liquid jet vacuum pump constituted by a jet 2 ofsmall diameter and a jet 3 of diameter larger than jet 2, a space 4being provided between the two jets.

Jet 2 opens into a threaded pipe 5 which is connected by a duct 6 to asource of pressurized fluid 7 or to the fluid escaping from the jack viaa distributor & supplying a jack 9 comprising a piston 9a.

Jet 3 opens into a threaded pipe 10 which is connected by a duct to aleakage nozzle 11 from which escapes a jet of air and which may beobturated by an obturation member 12 mounted at the end of the rod 9b ofthe jack 9. The space 4 located between the jets of the vacuum pump isconnected on the one hand to a valve seat 13 presenting orifices 13acapable of being obturated by a thin elastic washer 13b forming aone-way valve and it opens out on the other hand into a threaded pipe 14for output of a control signal itself connected by a duct 15 to a memberto be controlled, particularly a distributor 16.

The sensor functions in the following manner:

When the duct 6 is connected to the source of pressurizd fluid 7 and theobturator member 12 is in the position shown in FIG. 1, the fluidescapes through jet 11 towards the atmosphere and the vacuum pump 2, 3functions normally, ensuring opening of the valve 13 which is connectedto the atmosphere, the depression of the vacuum pump can therefore notbe created, the duct 15 therefore remains substantially at atmosphericpressure and no action of pressure or depression acts by duct 15,therefore no pneumatic signal acts on the distributor 16 which remainsstable. In fact, it is necessary to avoid "sucking" the slides ofdistributors, the latter having only to be pushed by a pressure signal.This is well effected by the invention thanks to the airing valve 13b.

The piston 9a moving in the direction of arrow F when it arrives at theend of stroke, the obturator member 12 obturates the nozzle 11 so thatthe fluid pressure delivers and increases in the space 4 of the vacuumpump and the valve 13b closes. The pressure propagates in the duct 15,giving a pressure signal which controls the distributor 16 of which theslide changes position. During the rod return stroke of the jack 9, (inthe direction opposite arrow F), the vacuum pump 2, 3 is again suppliedby the air escaping from the jack towards the atmosphere; the vacuumpump accelerates decontrol of the distributor 16 until the pressure isequal to atmospheric pressure, valve 13b automatically being on theatmosphere at the least depression. Decontrol is therefore much morerapid than by a natural emptying. The circuit 15 returns very rapidlysubstantially to atmospheric pressure.

The same would apply in the case of a permanent supply at input 17, thediagram shown making it possible to limit the duration of the leakage tothe sole duration of the supply of the jack and thus to limitconsumption of leakage air.

FIG. 2 shows a variant embodiment of a sensor in which a means foramplifying the signal allows the simultaneous and rapid control ofseveral distributors. This signal amplification means comprises achannel 18 in connection on one side with the supply input pipe 5 and onthe other side with a chamber 19 connected by a channel 20 to the pipe14 of the output signal.

The orifice of channel 18 is obturated by the central part of adiaphragm 21 or a piston subjected to the action of a spring 22 inabutment against a valve body 23. Upon obturation of the leakage nozzle11 of the fluid, the pressure in the sensor, acting on the whole of thediaphragm 21, opens the channel 18 releasing a considerable quantity offluid coming from the compressed air input towards the control output 14through the chamber 19 and the channel 20 which is connected thereto.

FIG. 3 shows a sensor in the form of a union in which the body 24 whichcomprises a conduit for passage 25 of which the input 5 is connected tothe source of pressurized fluid 7 by the distributor 8, said conduit 25being connected to the vacuum pump 2, 3 and presenting a pressurizedfluid output which is connected by a duct 26 to one of the chambers ofthe jack 9. The pipe 4 emitting the control signal is connected by aduct 27 to the input of the control means of the jack 8.

FIG. 4 shows a sensor which is constituted by a banjo union 31 and ascrew 28 mounted directly in a tapped hole 29 of an apparatus 30 whichsupplies the relay and the jack with compressed fluid. The banjo sensor31 is surmounted by a simple banjo 32. The direct supply circuit passesthrough 32 and the sensor 31 is supplied in by-pass.

In the embodiment of FIG. 5, the screw 28 is mounted on the distributor8, and the body 31 presents a pipe 10 connected to the leakage nozzle 11and a signal output pipe 14 connected to the input controlling thedistributor 8 by duct 27.

The other body 32 connects the pressurized fluid input by a pipe 33 tothe supply duct 26 of one of the chambers of jack 9.

In the embodiment of FIG. 6, the screw 28 is mounted on the body of thejack, the body 31 being connected by its pipe 10 to the leakage nozzle11, and the control signal output pipe 14 to the distributor 8 by a duct27. The other body 32 is connected by a duct 26 to the distributor 8.

FIG. 8 shows a union body in T form which is similar to that of FIG. 1,but in which the jets 2 and 3 of the vacuum pump are made directly inthe body and said body 1 of the sensor is associated with a T-union 34to ensure monitoring of the functioning of jack 9 (FIG. 8).

In FIG. 7, the outputs are instantaneous connections for tubes.

FIG. 9 shows an embodiment of a leakage nozzle 11 which is made in aplate 35 of an apparatus and which is connected by a duct 36 to the pipe10 of the relay.

On plate 35 moves a member 37 connected to a control means and which iscapable of obturating the orifice of the leakage nozzle 11 in accordancewith a known process but in the invention associated to interrupt theleakage.

FIGS. 10, 10a show a leakage nozzle 11 which is obturated by a valve 37subjected to the action of springs and comprising a ball 38 whichcooperates with a mobile member 39 fast in particular with a jack rod inaccordance with a known process, but in the invention associatedtherewith for the interruption of the leakage.

FIGS. 11, 11a shows a means for obturating the leakage nozzle which isintegrated in the body of the sensor. In this case, the leakage nozzle11 has its opening monitored by a valve 40 controlled by a lever 42against the action of a spring 41, said lever 42 being articulated aboutan axis 43 on the body 1 of the sensor and bearing at its other end aroller 44, cooperating with a mobile member 45 in the form of a cam, inorder to open and close the orifice of the nozzle 11.

FIGS. 12 and 12a show a sensor which is integrated at the end of thebody 46 of any apparatus, said body 46 being located opposite anobturator member 47 which, on sliding on the latter, obturates theleakage nozzle 11.

FIG. 13 shows a distributor comprising a body 48 in which is slidablymounted a slide 49 and which comprises at its two ends sensorsmonitoring the displacement of the slide. In fact, the ducts 14delivering a control signal during obturation of the leakage nozzles 11open opposite the ends of the slide 49 in order to displace the latterto the right or to the left. The input orifices of the sensors areconnected by ducts 50, 50a to the fluid input orifice in body 48 of thedistributor. The obturation of the leakage circuit may be effected allalong circuit 11. In particular, a "manual" control may be implanted oncircuit 11 in addition to the leakage circuit. The manual controlobturating the circuit (sic.). The pneumatic signal is transmitted byduct 14 to the distributor.

FIG. 14 shows a sensor mounted at one of the ends of the distributor asin FIG. 13, but the opening and closure of the leakage nozzle 11 aremonitored by a valve 51 which is made of magnetic metal actuated in thesensor of closure by an electro-magnet 52 connected to an electricalcircuit.

In FIG. 14 as in FIG. 15, a manual control of the signal may easily beobtained by stopping the leakage with the finger; the valve 51 may alsobe pushed on its seat for obturation of the leakage. The valve 51 mayalso be equipped with a push button to facilitate the manoeuvre with thefinger. A protection of the leakage may also be provided to avoiduntimely manual manoeuvres.

It may also be useful to dispose on the suction a protection againststopping the holes in the valve seat 13, with the fingers, which wouldprocure an untimely suction of the distributor slides. A filtration ofthe air may also be necessary for cleanliness of the seat of the valve.

FIG. 15 shows a sensor of which the body 1 is capable of being connectedto a fluid input duct by its threaded pipes 5, 5a. As in the precedingexample, the leakage nozzle 11 is monitored by a valve 51 actuated inthe sense of closure by an electro-magnet 52. The pneumatic signalleaves via pipe 14.

FIG. 16 shows a sensor of which the body 1 receives an enclosure 53 inwhich is disposed a contactor 54 of which the control member 55 is inabutment against a deformable diaphragm 56 obturating a chamber 57 inwhich opens out a duct 14 emitting a pressure signal upon obturation ofthe nozzle 11.

Consequently, there is produced a deformation of the diaphragm 56 whichactuates the member 55 of the contactor 54 which emits an electricalsignal corresponding to the pneumatic signal of the sensor.

FIGS. 15 and 16 constitute what is presently called electro-pneumaticinterfaces, converting thanks to the invention the pneumatic signal intoan electrical signal, and vice versa.

The invention finds its domain in the control of the cycles of pneumaticjacks, and in the pneumatic monitoring of the cycles of machines.

There are four possibilities of combining the apparatus with the deviceaccording to the invention:

1. The leakage circuit may either be integrated in the apparatus, orobturated by remote control.

2. The signal emitted by the sensor may either be integrated in theapparatus, or may remotely control a member.

The invention is, of course, non limiting and the man skilled in the artmay make modifications thereto without departing from the domain of theinvention.

We claim:
 1. An improved pneumatic sensor for the control of pneumaticcycles including in combination a fluid jet vacuum pump having an inletand an outlet and a pair of jets therebetween with a space between thejets, a source of compressed air, means connecting said source ofcompressed air to said inlet, a leakage nozzle, means connecting saidnozzle to said outlet, obturation of said nozzle provoking a rise inpressure in said vacuum pump, said rise in pressure being used as asignal for controlling a pneumatic component, means forming an outletorifice leading out of said space for emitting said control signal, aduct connected to said outlet orifice, and and valve means connected tosaid space and responsive to the increase in pressure in said outletduring obturation of said nozzle so that the supply pressure isestablished at the outlet orifice and the duct carries a pneumaticpressure signal and responsive to decrease in pressure in the outlet toadmit air into the space during flow out of the leakage nozzle toprevent reduction of pressure by the vacuum pump.
 2. An improved sensorincluding in combination a sensor body, means within said body formingtwo jets of a vacuum pump with a space between said jets, a firstorifice in said body forming an inlet to said vacuum pump, a source ofcompressed air, means connecting said source of compressed air to saidfirst orifice, a second orifice in said body forming an outlet for saidvacuum pump, a leakage nozzle connected to said second orifice, a thirdorifice in said body leading into said space, an output duct connectedto said third orifice for emitting a control signal, a fourth orifice insaid body leading into said space, and and valve means mounted in saidfourth orifice and responsive to the increase in pressure in said outletduring obstruction of said leakage nozzle and responsive to decrease inpressure in the outlet to admit air into said space during flow out ofthe leakage nozzle.
 3. An improved sensor as in claim 1 including anoutput amplifier of said control signal, said amplifier comprising aby-pass duct between said inlet and said outlet orifice and a valvecomprising a member for obturating said by-pass duct.
 4. An improvedsensor as in claim 2 including an output amplifier of said controlsignal carried by said body, said output amplifier comprising a by-passduct between said first orifice and said third orifice and a valvecomprising a member for obturating said by-pass duct.
 5. An improvedsensor as in claim 2 in which said body is formed with a duct forcompressed air, said duct having a pair of ends and a central part, saidsensor including a distributor and a jack having a chamber, meansconnecting one end of said duct to said distributor, means connectingthe other end of said duct to said jack chamber, and means connectingthe central part of said duct to the jets of said vacuum pump.
 6. Animproved sensor as in claim 2 in which said body is constituted as adouble banjo union comprising a pair of sub-bodies and a screw adaptedto be fixed to user apparatus, said screw being connected to saidcompressed air source, one of said sub-bodies containing said vacuumpump and said airing valve and comprising said first and second andthird orifices and said other sub-body being connected to an input andan output of compressed air for supplying another apparatus.
 7. Animproved sensor as in claim 1 including a control valve for regulatingthe opening of said leakage nozzle, a lever for operating said controlvalve, means mounting said lever for pivotal movement, a roller on saidlever and a movable element for actuating said roller.
 8. An improvedsensor as in claim 2 including a control valve on said body forregulating the opening of said leakage nozzle, a lever for operatingsaid control valve, means mounting said lever for pivotal movement onsaid body, a roller on said lever, and a movable member for actuatingsaid roller.
 9. An improved sensor as in claim 1 including a distributorcomprising an elongated body and an internal slide, said first-namedvacuum pump and leakage nozzle and airing valve being integrallyarranged at one end of said elongated body, a second vacuum pump, asecond leakage nozzle and a second airing valve integrally arranged atthe other end of said elongated body, a duct in said elongated bodyconnecting the inlets of said vacuum pumps to said compressed airsource, said outlet orifices applying said control signals to the endsof said slide.
 10. An improved sensor as in claim 2 including adistributor comprising an elongated distributor body and an internalslide, means arranging said first named sensor body integrally with oneend of said distributor body with said third orifice communicating withthe interior of said distributor body at one end of said slide, a secondsensor body, means integrally arranging said second sensor body with theother end of said distributor body with the third orifice of the secondbody communicating with the interior of the distributor body at theother end of said slide, a duct in said distributor body connecting thefirst orifices of said sensor bodies to said source of compressed air,said third orifices applying said control signals to the ends of saidslides.
 11. Improvement in sensors according to any one of claims 1 to10, characterized in that the obturation of the orifice of the leakagenozzle 11 is controlled by a valve 51, controlled by an electrical means52, or pneumatic, or manual.
 12. Improvement in sensors according to anyone of claims 1 to 10, characterized in that the pneumatic controlsignal acts on a means 53, 55, 56 converting the pneumatic signal intoan electrical signal.